Genuine BMW timing chain guide rail for the N63/S63 4.4L V8. The guide rails keep the timing chain tracking properly as it runs around the sprockets; the plastic-faced rail wears from years of chain contact, and a worn rail lets the chain run loose and noisy, eventually risking chain skip if left unaddressed. Factory-spec replacement manufactured to BMW's exact tolerances.

Fitment: BMW N63/S63 4.4L V8 models - E70 X5, E71 X6, F01/F02 750i/750Li (incl. Alpina B7), F07/F10 550i, F12/F13 650i (confirm exact rail position at checkout).